It has been previously demonstrated that n-channel inversion layers may be formed on the surface of p-type InP as disclosed in the U.S. patent application of David A. Collins et al., for NORMALLY OFF InP FIELD EFFECT TRANSISTOR, Ser. No. 72,399, filed Sept. 4, 1979. As disclosed by Collins et al., metal-insulator-semiconductor field-effect transistors (MISFET) utilizing these layers have been fabricated which exhibit normally off behavior with essentially constant gain from d. c. to 1 MHz. The device disclosed by Collins et al., was constructed on a 100-oriented p-type bulk substrate with a carrier density approximately 10.times.10.sup.16 centimeter.sup.-3. Although demonstrating the potential of this device, it is believed that the high carrier density of this material results in large parasitic capacitances between the source, drain, and gate contact pads and the substrate which in turn severely limits the utility of the device by precluding the possibility of microwave power gain.